你是否曾经思考过为什么鸟儿不会被通过高压线的电流电击吗？


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选材／校对／翻译：hqj5715
It's not unusual to see rows of birds perched on power lines. But did you ever wonder why birds aren't electrocuted by the enormous currents that flow through these high-voltage wires? You might think it's because the wires are insulated, but they're actually not insulated at all — that's why downed power lines are so dangerous. No, the only reason why birds on power lines usually aren't electrocuted is because the wire is the only thing they're touching! Like all energy, electricity seeks equilibrium, or balance. That means electricity will flow from high-energy areas to areas of less energy, always using the path of least resistance. So if the bird has one foot on our original wire, and the other foot on, for example, the ground or on a different wire with less voltage, the bird would be electrocuted. Because the electricity would pass through the bird on its way from the high-voltage line to the lower-voltage line or the ground. But as long as both of the bird's feet are on the same wire (or wires of the same voltage), the bird is safe. The current doesn't have anywhere else to go, so the electricity won't pass through the bird–it stays on the path of least resistance, the wire.
我们经常看到成对的鸟儿栖息于高压电线上。但是你是否曾经思考过为什么鸟儿不会被通过高压线的电流电击吗？ 你也许会认为是电线绝缘的原因，但是他们实际上并不绝缘--这也是垂下的电线非常危险的原因。事实上，鸟儿站在电线上而没有被电击的唯一原因是电线是鸟儿唯一碰触到的东西。 电能像所有的能量一样倾向于去极化或者说平衡。这表示电能会从高能量的区域流向低能量的区域，经常选择的是电阻比较低得路径。因此，如果鸟儿的一只脚站在我们开始讲的电线上，而另一只脚站在例如地面或者另一个电压较低的电线上的话，那么鸟儿将会被电击。电能将会从高电压的线路上流向低电压的线路或者是地面而穿过鸟儿的身体。 但是，只要鸟儿的两只脚都站在同一根电线上，鸟儿便是安全的。电流便不能流动，因此也不能穿过鸟儿的身体--电流保持在低电阻的通道上，即电线。